Researchers say they have found strong evidence to support the theory that life on Earth could have been seeded by debris from outer space.
A meteorite found in Chile’s Antarctica could lend weight to the argument that life on Earth may have resulted from debris falling on our planet from outer space, scientists from America’s Arizona State University are claiming.
Many theories suggest that Earth initially did not possess the molecules needed to begin primitive life. Scientists like Sandra Pizzarello, a leading researcher from ASU’s epartment of Chemistry and Biochemistry, have been searching for an answer to what caused life on earth to begin.
The 4 gram meteorite dubbed Grave Nunataks 95229 after its place of discovery in Antarctica, contains traces of the element nitrogen found in the proteins and DNA that form the basis of life as we know it.
Details of the study, Abundant Ammonia in Primitive Asteroids and the case for a Possible Exobiology, surfaced this Monday, March 14, in a journal from the United States’ National Academy of Sciences.
Meteorites like this could have supplied the early Earth with enough nitrogen in the right form for primitive life forms to emerge, explains Pizzarello. “All origins-of-life theories need to account for a sustained source of reduced nitrogen, in order to make amino acids and nucleobases.”
The work was made possible by finding exceptionally pristine, ammonia-containing asteroidal meteorites in Chile’s Antarctica. The ice in this region, Pizzarello explains, is a good ‘curator’ of meteorites. After one impacts in the Antarctic it is quickly covered by snow and buried in the ice. Because the ices are in constant motion, when they come to a mountain they flow over the hard land and bring the rocks to the surface.
Many such meteorites have been studied over the last decade and several have been found to contain organic molecules that were almost certainly produced in a cosmochemical environment. The bodies, however, contain many different types of organic molecule and it is still difficult to put forward a strong theory that explains how these could have eventually led to life.